Todd Bowles arrived at the NoveCare Complex on Tuesday around 5:30 a.m. He had just finished running on the treadmill with fellow coaches Duce Staley and Mike Caldwell, and he went to the cafeteria for breakfast when Andy Reid called Bowles to his office.

Reid informed Bowles that the Eagles made a change at defensive coordinator, firing Juan Castillo and reassigning Bowles.

Just like that, Bowles became a defensive coordinator for the first time in his NFL career. It is now up to the Temple product to resuscitate the Eagles' defense and perhaps save Reid's job.

Bowles admitted to initial shock on Tuesday when he learned of his new role. But he's also conditioned himself for this type of change. One year ago, Bowles had a similar meeting when Miami Dolphins coach Tony Sparano was fired with three games remaining last season, and Bowles was promoted to interim head coach.

"In this game, you kind of see things every year that make you surprised until you stop being surprised," said Bowles, who wore a Temple sweatshirt while meeting with reporters on Tuesday. "It's the profession we choose. If you win, you're great. If you lose, you stink."

Bowles must find a way to help the Eagles win more frequently, and that includes preserving fourth-quarter leads. The Eagles have allowed 49 fourth-quarter points this season, the most of any quarter. They've squandered fourth-quarter leads in the last two games, a trend that dates back to last season. Part of the responsibility for fixing that issue is in-game adjustments. Bowles must prove capable to adjust on the fly even though he's never called an NFL defense before.

"As a staff, we put the game plan together, and you just watch enough film and trust your instincts enough to make calls and make sure everybody's on the same page," Bowles said. "And you try to take away what they're doing yet not expose what you're doing."

Bowles said he does not plan any major schematic changes. The Eagles will still run the wide nine defensive line alignment that defensive line coach Jim Washburn teaches and will continue to mix man and zone coverages with the defensive backfield.

The coaching staff is undergoing a self-scouting phase. After that, Bowles will have a better idea of what needs tweaking. Reid said Bowles will have the chance to put his own imprint on the Eagles defense, although Reid also emphasized that he does not expect a transition period.

"You take the defense and you build your personality with that as a coordinator," Reid said. "And you have some flexibility here. So you just got to let your personality show within it."

Since the Eagles hired Bowles in January, he seemed a natural replacement if Castillo struggled. Both Reid and Bowles disputed on Tuesday the notion that Bowles was hired with this contingency in mind. When owner Jeffrey Lurie discussed Reid's decision to retain Castillo before the season, Lurie specifically mentioned the added leadership of Bowles.

"We wanted another communicator for Juan," Reid said. "Someone he could talk to who has experience. That's why I brought [Bowles] here."

Bowles played eight seasons in the NFL from 1986-1993 before starting a coaching career. He became an NFL assistant with the New York Jets in 2000 and has since been on coaching staffs in Cleveland, Dallas, and Miami. Bill Parcells hired Bowles at three of those four stops. Parcells often ran a defensive scheme different than the one the Eagles favor, but Bowles said he has been in football long enough and has spent enough time with the Eagles to understand the scheme.

"The 4-3 has been around a long time, and this is not a new system," Bowles said. "They put the ends a yard wider, and everyone thinks this is a new system. It's been around for a long time."

What will be new for Bowles are his day-to-day duties and the amount of players he oversees. As the secondary coach, Bowles needed to worry about only the cornerbacks and safeties and did not spend much time preparing for running plays. Bowles said he's familiar with the entire defense and has been in meetings with the players throughout the season.

When Bowles started working for Parcells, Parcells instructed Bowles to learn the entire system and all the players, not just the group he oversees. That way, he'd always be prepared if a change is made. Bowles heeded that advice, and now he's again in the spotlight after a change was made.

"I don't think it will change from [the players'] end. They're hearing the same message from a different person," Bowles said. "I might have a different spin on it and my own ideas here or there and a few tweaks that they go through."